When
Taubes makes his case for the high carbohydrate diet being the cause of obesity
rather than the high fat diet he discusses a number of interesting case
studies. The Sioux and Inuit for instance ate almost exclusively meat, which is
high protein/high fat/low carb. Even though fruits and vegetables were
basically non-existent in their diets these populations were very healthy. It
was only with the introduction of the foods of European settlers that these
tribes experienced diabetes, obesity, and heart disease.
The
typical treatment for obesity is calorie reduction and more exercise. However,
most of the studies that drastically reduced calories by reducing fat intake led
to ravenous hunger and lethargy. Not only were results abysmal but in one study
the subjects became so hungry that when they were finally allowed to eat as
desired they ate 8,000 calories a day. This led them to gain 5 percent more
weight than when they had started the study and have 50 percent more body fat. Another
study showed that an 18 month marathon training program led to an average loss
of 5 pounds of body fat for men and no change for women.
Many
of us are familiar with the phrase “a calorie is a calorie.” This means that
whether you’re eating a calorie of protein, fat, or carbohydrate you’re getting
the same amount of energy. Thus, in order to lose body fat it shouldn’t matter
what you eat as long as calories are reduced. However, Taubes points out that
different nutrients have vastly different effects on metabolism and hormone secretion.
Insulin secretion for instance is dramatically increased by the consumption of
refined carbohydrates. Insulin is the only hormone capable of shuttling fatty
acids and glucose into fat cells where it stores them as fat.
The
main argument against the research Taubes discusses is that it seems to defy
the laws of physics; according to Jane Brody, “Eat more calories than your body
uses and you will gain weight. Eat fewer calories and you will lose weight. The
body … knows no other arithmetic.” In defense Taubes discusses an interesting
hypothesis. Instead of overeating and lack of exercise being the cause of
weight gain, what if we “eat more, move less, and have less energy to expend
because we are metabolically or hormonally driven to get fat?” The body gets so
good at fat storage that it creates an “internal starvation” for the other
tissues causing you to consume more calories and be lethargic. Since insulin is
“the primary regulator of fat storage” it would appear high levels of insulin
due to overconsumption of refined carbohydrates is the problem.
In
the end Taubes suggests a compromise with the saturated fat/cholesterol
hypothesis into a diet that “might do us good and probably won’t do harm.” “The
current conception of a healthy diet is one that minimizes salt content and
maximizes fiber; has plenty of good fats (monounsaturated and omega-three
polyunsaturated fats) and minimal bad fats (saturated and trans fats); has
plenty of olive oil and fish, and little red meat, butter, lard, and dairy
products. When meat is consumed, it’s lean … Dairy is low-fat or no-fat. The
diet has plenty of nuts and legumes and good carbohydrates … (vegetables,
fruits, and unrefined grains), but few bad carbohydrates ... (highly refined
carbohydrates and sugars).”
In Part 3 I'll discuss the limitations to the research.
Stay fit,
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